Method and apparatus for obtaining indications of earth formations



H. L. @QWERTY METHOD AND APPARATUS FOR OBTAINING INDICATIONS 0F EARTHFQRMAIIONS Filed June 2S, 1925 Patented Dec. 29, 1931 HENRY L. BERT?, OFNEW YORK, N. Y.

MHOD APPARATUS FOR OBTAININGNDICATIONS 0F EARTH FORMATIONS. I

4n'rENioFFrcE Tram K Application led June 29, 1925. Serial No. 40,140.

rlFhis invention relates to the development ing wells are the cabledrilling system andv the rotary system. Where the formations l@ throughwhich the well is to be drilled are not sufciently consolidated topermit the sides of the hole to sand up or to prevent caving whendrilling very deep wells, it is customary to use the rotary system ofdrilling. ln this 35 system a mud laden fluid is kept constantlycirculating down through the inside of the drillstem andythrough a holein the bit at the Y bottom of the well and up the outside of the stem,the pulverized material loosened by the 2Q bit being carried up out ofthe well by the cir-v culating medium. One of the disadvantages of therotary system is that smaller oil and gas sands and important reservoirsmay be passed through in prospecting due to the fact I that the heavycolumn of water or mud uid which must be used in a rotary hole puts so imuch pressure up'on the formations that oil or gas under lower pressurewill not How into the well.

method and apparatus whereby the well may be readily tested to ascertainwhether or not Y oil or gas formations have been reached.

Briefly stated the method consists in elevating the column of mud fluidin the well in such a manner that the pressure of the same at the bottomof the well is suciently reduced to permitthe fluids naturally occurringin the earth formations which have been penetrated to flow. into thewell in the region of reduced pressure, and bringing the iuids whichhave flo-Wed into he Well to the top thereof by Giri; from the top ofthe well to force the piston culating the mud iuid. Generally stated,the apparatus for practising the method consists of a piston which isplaced in the well as near the bottom thereof as practicable, meansbeing provided for elevating the piston and the column of mud 150 fluidthereabove.

In .the practise of the invention, it is contemplated that a pistonshall be placed in the annular space between the drill pipe and walls orcasing of the well hole, means being provided in the piston to permitthe mud te laden duid which has reached the bottoni of the well to passupwardly therethrough to the top of the well, such means includingone-way .valves to prevent the flow ofthe fluid downwardly through thepiston. When te it is desired to ascertain if oil and fgas formationshave been reached, the piston is moved upwardly in the well a suitabledistance by 'cables leadingv from'the piston to a hoisting 'mechanism atthe top ofthe well. 'W hen the piston is lifted it will also lift thecolumn of mud laden fluid thereabove. Vfhile the piston is being raisedthe flow of mud laden fluid through the drill pipe is preferablystopped. The piston is raised sufhciently 7@ far to reduce the pressureat the bottom ofthe well below that occurring in the oil or gasformations or is lifted sufficiently far to create a vacuum in thebottom of the well to induce the oil and gas to liow' into the region g5of reduced pressure. When the piston has been elevatedas stated and asucient time has elapsed to permit oil and gas from the formations, ifthey should be present, to dow into the region of reduced pressure belowthe so piston, circulation of mud fluid is again started in order toforce or carry to the top 'of the well, any oil and gas which may haveflowed into the well.

After the oil and gas which have flowedl te into the region of reducedpressure below the piston have been forced out of the well by thecirculation of the mud fluid, the piston may again be lowered byreversing the direction of circulation of the mud fluid, that is to say,9o by forcing mud fluid Iinto the annular space between the drill pipeand walls of the well downwardly, thermud fluid in the drill pipe beingforced upwardly bythe piston as it moves downwardly.

When the piston has been lowered to the desired position, the well isoperated as before by' forcing mud fluid down through the drill pipe tothe bit and into the bottom of the well from whence it ilows upwardly onthe outside of the drill pipe, as will now be readily understood. Thepiston may be raised as frequently as may be found desirable to obtaininformation concerning the formations which are being drilled, and mayobviously be lowered just as frequently. The piston is readily loweredin the well, even though there may be considerable pressure in the gasand oil formations, due to the weight of the column of mud-laden fluidthereabove. It will also be appreciated that due to the weight of themud-laden fluid above the piston, there is little or no danger of thegas and oil blowing the piston through the well and thus wrecking theequipment.

The distance through which the piston and the column of mud-laden fluidthereabove must be raised to induce a flow of oil into the bottom of thewell will obviously depend on the pressure eXistin on the oil or gas.However it will seldomie necessary to move the piston through a distancegreater than 30 feet in order to create a sufficiently reduced pressurein the well to get the desired samples.

The above and other features of the invention will more fully appearfrom the detailed description taken in connection with the accompanyingdrawings, and will be set forth in the appended claims, it beingpremised that various changes may be resorted to without departing fromthe spirit of the invention.

For further understanding of the invention, reference is made to thedetailed dei scription taken in connectionwith drawings forming part ofthis specification.

Referring to the drawings Fig. l is a view partly in elevation andpartly in section of a well showing the equipment for drilling the wellby the rotary method, the piston and elevating means therefore beingalso shown;

Fig. 2 is an enlarged vertical section through the lower part of thewell showing more in detail the construction of the piston and itsposition with respect to the drill pipe land casing;

Fig. 3 is a transverse section on line 3 3 of Fig. 2 showing the top ofthe piston; and

Fig. 4 is a transverse section on line 4,-.-4 of Fig. 2 showing the'ringwhich is connected to a set of valves which are adapted to be opened bythe drill bit when the drill pipe is to be withdrawn from the well.

In the drawings, numeral 10 indicates a rotary bit of any preferred orapproved construction, 11 the strata being drilled, 12 the drill pipe orstem to which the bit is connected and through which a mud laden Huid isada ted to be passed by a suitable conduit 13' at t e top of the pipe,the bit having a hole or opening 14 through which the mud fluid passesinto the well. 16 indicates a casing with which the well hole ispreferably, though not necessarily, cased as the drilling proceeds.Located in the casing as near to the lower end thereof as practical is apiston 18 which is provided with a central opening through which thedrill pipe passes in as fluid-tight manner as possible, but notsutliciently tight to prevent the pipe from rotating or from having thenecessary longitudinal movement therein. A suitable packing generallyindicated at 20 is preferably provided between the `'drill pipe andpiston to more readily enable a satisfactory fluid-tight joint to bemaintained therebetween. A suitable packing is also provided between thepiston and the wel] casing to enable the fluid-tight joint to ybemaintained therebetween, said packing being generally indicated at 22.

ln order to permit the mud laden fluid which has reached the bottom ofthe well lto pass upwardly, the piston is provided with a plurality ofports or passages 24, at the tops of which are suitable valves toprevent back flow of the fluid. These valves may be of any suitable orpreferred form but for convenience of illustration they have been shownas ball valves 26, the same being held in place by suitable cages 28.

Connected to the piston for4 the purpose of raising the same are aplurality of cables 30, preferably three in number, suitable anchors 32being affixed to the piston to facilitate the securement of the cablesthereto. The cables 30 pass through the well cap 34 and over pulleys 36suitably supported on the cap and lead to a suitable hoisting mechanism,not shown.

As previously indicated, the well is preferably, though not invariablyor necessarily, cased as the drilling proceeds. When a cas ing isemployed,as is preferable, the piston is lowered with the casing. Whenno casing is employed, the piston may be secured to the drill pipe insuch a manner that it will becarried down ,into the hole as the drillingproceeds. The piston in either case will serve as a centering device forthe drill with the result that a straighter and rounder hole may bemade. While the drill is in operation, mud fluid is beingforcedthroughthe drill pipe and bit to the bottom of the well, the mudHuid passing upwardly from the -bottom of the well through the passages24 and by the valves 26 in the piston as will now be readily understood.

When it is desired to ascertain if oil or gas formations have beenreached by the drill, the iiow of mud Huid through the drill pipe isstopped and the piston raised a sutiicient distance to create asuctionor to reduce the pressure din the bottom of the well. If any oilor gas is present in the surrounding formations, the same will flow intothe well by reason of reduced pressure therein. In order to bring theoil and as'to the surface, circulation of the mud fluid is again startedwith the result that the oil or gas or water withdraw the piston.However, it will usually be desirable to leave the mud fluid inthe wellduring such operation. To effect this, the piston is provided withpassages 40 having valves 42 at the top thereof, each of said valveshaving av stem 44 extending downwardly through the passage and'below thepiston. Flexibly connected to the lower end of the stems is a ring 46through which the drill pipe passes. When the drill pipe is lifted thetop of the bit 10 will strike the ring 46 and thus lift the valves 42and thus permit the mud fluid to flow through the piston as the pistonis carried upwardly with the drill pipe and bit. In order that the ringmay not close the passages 40, the bottom of the piston is preferablyprovided with a downwardly extending annular lug or shoulder 48 againstwhich the ring will abut without closing the passages 44 as will bereadily understood.

The turntable for rotating the drill pipe is indicated at 50 theturntable being driven in the usual or any preferred manner as by apinion 52 on a shaft 54 which in turn is driven in any suitable manner.`The turntable is supported above the well cap 34 in such a manner as notto interfere with the cables passing through the latter.

Various changes in the details of construction of the apparatus mayobviously be resorted to without departing from the spirit of invention.Furthermore the term drilling tool is not to be understood as meaningnecessarily a rotary drill but is intended to be. a term of descriptionapplying to any drilling. tool capable of use with a mud fluid method ofdrilling. 2

The invention having been described, what is claimed as new is:

l. The step in a method of determining the presence of hydrocarbonfluids' during drilling operations in a well wherein the pressure of acirculating mud fluid employed during drilling operations normallyprevents the entrance 'of surrounding hydrocarbon fluids into the well,which comprises temporarily' reducing the mud fluid pressure at thefootof the well sufficiently to permit inflow of said hydrocarbon fluids,whilegontinuing the drilling operation.

2. In determining the resence of hydrocarbon fluids in a well W ereinthe pressure of a circulating mnd fluid employed during drillingoperations normally prevents the entrance-of surrounding hydrocarbonfluids into the well the step comprising temporarily reducing the mudfluid pressure at the foot of the well sufficiently to permit influx? ofsaid hydrocarbon fluids while leaving the drilling toolwithin the well,said pressure being reduced by bodily elevating a substantial lpart ofthemud fluid Within the Well, and temporarily reversing the direction ofcirculation of the mud fluid preparatory to a new determination. v

3. The step in a method of determinino the presence of hydrocarbonfluids during drill'- ing operations in a well wherein the pressure of acirculating mud fluid employed during drilling operations normallyprevents. the

Aentrance of surrounding hydrocarbon fluids into the well, whichcomprises temporarily reducing the mud fluid pressure at the foot of thewell sufficiently to permit inflow of said hydrocarbon fluids, saidpressure being reduced by bodily lifting a substantial part of the mudfluid within the well, while leaving the drilling tool in place in thebottom of the well.

4. A method of determining the presence of hydrocarbon uids duringdrilling operations in a well wherein the pressure of a circulating mudfluid employed during rotary drilling operations normally prevents theentrance of vsurrounding hydrocarbon fluids into the Well, comprisingleaving the drilling tool in place within the well, reducing the.pressure of the mud fluid' at the foot of the well and bringing enteredhydrocarbon fluids to the top of the well by circulating fluid throu hthe well.

5. method of determining the presence of hydrocarbon fluids duringdrilling operations ina well wherein the pressure of a column ofcirculating mud fluid employed in the well during rotary drillingoperations nrmally prevents the entrance of surrounding hydrocarbonfluids into the well, comp-rising leaving the drilling tool in placewithin the well, reducing the pressure of the .-mud fluid at the foot ofthe well by bodily elevating the column of'mud fluid, and bringing4entered hydrocarbon fluids to the top of the well by circulating fluidthrough the well.

-6. In combination, a well drilling tool, a

piston'between the vdrillingtool and walls of mitting the mud fluid topass upwardly therethrough from the bottom of the well, and means forelevating the piston to create. a region of reduced pressure between thepiston and bottom of the well.

8. In combination, a drilling tool for drilling a well, a piston throughwhich the drilling tool passes, means associated with the drilling toolpermitting mud fluid 4to be passed to the bottom of the well, meansassociated with the piston permitting mud fluid reaching the bottom ofthe well to pass upwardly through the piston but not back therethrough,and elevating means secured to the piston whereby the same may be raisedto create a region of reduced pressure in the lower part of the well. f-

9. In combination, means for drilling a well comprisinga hollow drillstem and bit through which a mud fluid may be passed to the bottom of awell, a well casing, a piston surrounding the drill stem and beingslidably engaged with the casing, valves in the piston through which themud Huid reaching the bottom of the well may pass through 'on its way tothe top of the well, and lifting means secured to the piston for raisingthe piston in the casing to create a region of reduced pressure in thebottom of the well.

10. In combination, means for drilling a well comprising a tool havingmeans through which mud fluid may be passed to the bottom of the well. acasing, an annular piston filling the space between the drilling tooland casing, said tool being movable with respect to the piston .and thelatter being slidably mounted with respect to the casing, valves in thepiston through which mud fluid may pass in an upward direction from thebottom of the well, and means for raising the piston in the well tocreate a region of reduced pressure in the bottom of the well to induceoil and gas from the surrounding strata to How into said region.

11./)The combination with a drilling tool adapted for drilling a wellwhich is filled with mud fluid, of' a` piston in the annular spacebetween the walls of the well and the drilling tool, means permittingthe piston to be carried upwardly with the drilling tool withoutelevating the column of mud fluid, said means comprising valves in thepiston which are adapted to be opened to permit the mud fluid to flowtherethrough as the piston is elevated by the drilling tool.

12. The combination with a drilling tool adapted for drilling a wellwhich is filled- With mud Huid, of 'a piston in the annular spacebetween the walls of the well and the drilling tool, means permittingthe piston to be carried upwardly with the drilling tool withoutelevating the column of mud fluid, said means 'comprising valves in thepiston and means movable by the drilling tool for opening said valvesbefore the piston is elevated by the drilling tool, said valves whenopened permitting the piston tov be moved through the mud fluid withoutelevating it.

13. The combination with a drilling tool adapted for drilling a wellwhich is filled with mud fluid, of a piston in the annular space betweenthe walls of the well and the drilling tool, means permitting the pistonto HENRY L. DOHERTY.

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